Blood-tissue surface based radiosurgical renal treatment planning

ABSTRACT

Devices, systems, and methods for planning radiosurgical treatments for neuromodulating a portion of the renovascular system may be used to plan radiosurgical neuromodulation treatments for conditions or disease associated with elevated central sympathetic drive. The renal nerves may be located and targeted at the level of the ganglion and/or at postganglionic positions, as well as preganglionic positions. Target regions include the renal plexus, celiac ganglion, the superior mesenteric ganglion, the aorticorenal ganglion and the aortic plexus. Planning of radiosurgical treatments will optionally employ a graphical representation of a blood/tissue interface adjacent these targets.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims priority to and is a continuation ofPCT/US2013/077176, filed Dec. 20, 2013, entitled “BLOOD-TISSUE SURFACEBASED RADIOSURGICAL RENAL TREATMENT PLANNING”, which claims the benefitunder 35 U.S.C. §119(e) of U.S. provisional application No. 61/746,738,filed Dec. 28, 2012, entitled “BLOOD-TISSUE SURFACE BASED RADIOSURGICALRENAL TREATMENT PLANNING”, the contents of which are incorporated hereinby reference in their entirety.

BACKGROUND OF THE DISCLOSURE

Radiosurgery is a medical procedure that allows non-invasive treatmentof tumors and other targets in the head, spine, abdomen, heart, andlungs. During radiosurgery, a series of beams of ionizing radiation areoften directed from outside a patient so as to converge at a targetregion. The radiation beams often comprises MeV X-ray beams fired fromdifferent positions and orientations. The beam trajectories help limitradiation exposure to the intermediate and other collateral tissues,while the cumulative radiation dose at the target can alter or treat thetissue. The distribution of beams may be in three dimensions or two andfurther, the beams of ionizing radiation may be delivered to targettissue in a single procedure or multiple procedures. The CYBERKNIFEradiosurgical system (Accuray Inc.) and the TRILOGY radiosurgical system(Varian Medical Systems) are two known radiosurgical treatment systems.

Radiosurgical treatment of portions of a patient's renovascular systemhas been proposed as a treatment for hypertension. The link betweenhypertension and kidney function was uncovered when patients withend-stage renal disease underwent surgical removal of a kidney andthereafter showed a reduction in blood pressure and total systemicresistance. More specifically, it was discovered that hyperactivity ofthe nerves surrounding the renal arteries is linked to hypertension, theprogression to chronic kidney disease, and heart failure. Since thediscovery, renal denervation was proposed to reduce sympathetic outflowto the kidneys, increase urine output (naturiesis and diuresis) andthereby reduce rennin disease without adversely affecting otherfunctions of the kidneys (e.g., glomerular filtration rate and/or renalblood flow).

Traditional treatments include ablation of the origin of the renalnerves in the sympathetic ganglia, pharmacological treatments, anddevice-based approaches. These approaches, however, each had variousshortcomings. Ablating the origin of the renal nerves in the sympatheticganglia has historically been considered very difficult. Pharmacologicassault on nerve functions is associated with systemic complications.Moreover, the sympathetic renal nerves arborize throughout the walls ofthe renal arteries and frustrate access thereto. As such, radiosurgicaltreatment has been proposed to deposit a sufficient ionizing radiationdose at a target of the renovascular system to ablate or modulate aportion of the renal nerves so as to reduce neural activity of thenerves, particularly the renal nerves located proximate to the renalarteries. The renovascular system may be located and targeted at thelevel of the ganglion and/or at postganglionic positions as well as atpreganglionic positions.

Although there have been proposed advancements in radiosurgical renaldenervation, it is still difficult and cumbersome to plan radiosurgicaltreatments for renal neuromodulation. In standard radiosurgicaltreatments of tumors and the like, computed tomography (CT) imagingprovides a series of planar X-ray scans. For the X-rays adjacent atumor, the planning physician draws a boundary of the target tissue,with the boundary being drawn on the scan traversing through the tumorand the boundary encompassing the tumor (and typically including someadditional offset or margin of treated tissue for safety). As the tumoris typically contained within one organ (but may alternatively extendbeyond the organ surface to an adjacent organ) the planned treatmentboundary is fairy independent of tissue/tissue interface contours.Hence, the treatment plan is typically drawn up as a series of circlessurrounding the tumor on each CT scan in which the tumor is visible.

It is difficult to draw an appropriate radiosurgical renovasculartreatment plan for forming patterns on conventional planar CT scansusing standard radiosurgical planning interfaces. A physician mustevaluate the multiple CT scans, and draw appropriate lesion lines and/orcircles representing a treatment plan at each planar slice of the targetregion of the renovascular system. The physician must be able tovisualize desired treatment areas from each planar scan. While thisappears to be a mere inconvenience, work in connection with the presentinvention indicates it is surprisingly difficult to efficientlyestablish an renovascular treatment plan using existing radiosurgicaltreatment planning tools in light of the location and size of potentialtargets in the renovascular system.

In light of the above, the present inventors have determined that it isdesirable to provide improved devices, systems, and methods for planninga radiosurgical treatment for alleviating renovascular hypertension. Itwould be particularly beneficial if these improvements were compatiblewith (and could be implemented by modification of) existingradiosurgical systems, ideally without significantly increasing theexposure of patients to incidental imaging radiation, without increasingthe system costs so much as to make these treatments unavailable to manypatients, without unnecessarily degrading the accuracy of thetreatments, and/or without causing unnecessary collateral damage to thehealthy tissues of the patient, including to endothelial tissues of thevasculature adjacent a target tissue.

SUMMARY OF THE DISCLOSURE

The present invention generally provides improved devices, systems, andmethods for planning radiosurgical treatments for alleviatingrenovascular hypertension. Certain embodiments of the invention mayprovide a three-dimensional model of a renovascular target region whichmay help a physician better visualize the target region. Athree-dimensional model of a blood/vessel boundary surface of a bloodvessel adjacent to a renovascular nerve may be provided. Certainembodiments may receive input with reference to a radiation target whichis offset from a three-dimensional model of blood/vessel boundarysurface and/or may generate a three-dimensional model of an estimatedtarget location by radially offsetting a distance from a blood/vesselboundary surface of a blood vessel adjacent to the renovascular target.Such embodiments may optionally receive input regarding a radiationtarget on an estimated target location surface. The input of the desiredradiation target may be facilitated by snapping and extending an inputtarget onto (or to a desired offset from) a three-dimensional modelbased on a user's input relative to a graphical representation of thethree-dimensional model. Additional embodiments may receive an inputtarget on a three-dimensional model of a blood/vessel boundary surfaceand may offset the input target a distance from the three-dimensionalmodel of the blood/vessel boundary surface. Some embodiments provide aneural altering dose of radiation at an offset target site and a safeluminal dose of radiation at the blood/tissue boundary. Further someembodiments may allow a physician to better visualize the overalldesired radiation target over the treatment area by displaying theinputted target relative to a surface model. Certain embodiments maydisplay a dose cloud relative to the three-dimensional model to allow aphysician to better visualize the radiation dose at portions of thetarget region according to the inputted treatment plan.

For example, in some exemplary embodiments a radiosurgical method foraltering neural function of a patient body is provided. The methodincludes acquiring image data from a blood vessel adjacent to a nerve. Athree dimensional model is generated from the image data by identifyinga boundary surface between the blood vessel and blood flowing thereinfrom the image data. An input identifying a radiation target, which isoffset from the blood/vessel boundary surface, is received withreference to an image of the three-dimensional model. An irradiationtreatment of the radiation target may then be planned so as to provide aneural function-altering dose of radiation at the target and a safeluminal dose of radiation at the blood/vessel boundary. Optionally, thenerve adjacent to the imaged blood vessel may be the renal plexus andthe irradiation treatment may be configured to provide a decreasing dosegradient between the target and the blood/vessel boundary. The imagedata may be from an aorta or a renal artery. The radiation target may beoffset from the blood/vessel boundary surface by an offset distance in arange from about 0.25 mm to about 6 mm. Additionally, the radiationtarget may vary longitudinally along the boundary surface and may varywithin a range from about 0.5 mm to about 3.0 mm.

The method above may further include adjusting a pattern of beams of theradiation to compensate for movement of the blood vessel wall. Themovement of the blood vessel wall may be due to a patient's respiration,a heartbeat or a bodily shift of the patient. The method may includeoutputting the ionizing radiation treatment pattern onto a plurality ofslices of two-dimensional image data. In some embodiments input may bereceived on a display. The display may facilitate the input by snappingthe input of the radiation target to a location relative thethree-dimensional model. Further, embodiments may utilize a threedimensional model surface which is radially offset from the identifiedblood/vessel boundary surface and the display may facilitate the inputby snapping the input of the radiation target onto the surface of themodel.

In some embodiments the method may further include expanding a treatmentpattern of intersecting radiation beams along a longitudinal axis of theblood/vessel boundary surface such that renal nerve activity is reducedso as to treat diseases and conditions related to hyperactivity of thesympathetic renal nerves, such as renal hypertension. The method mayinclude generating an ionizing radiation treatment plan based on thetreatment pattern and projecting a dose cloud to the three dimensionalmodel based upon the treatment pattern so as to verify the dose ofradiation along the blood/vessel boundary is sufficiently low to inhibithyperplasia. The expected consequence of high doses of radiation on alarge artery is thickening of the vessel wall and consequent stenosis ofthe vessel. The radiation target may include one or more annularcircumferential segments. The nerve adjacent to the blood vessel may beone of a celiac ganglion, a superior mesenteric ganglion, anaorticorenal ganglion, nerves in the renal ostium region, and nerves inthe renal artery branching region.

In other embodiments, a radiosurgical system for denervation of apatient body is provided. The system includes an image capture devicefor acquiring image data from a blood vessel adjacent to a nerve. Aprocessor system can couple the image capture device to a display. Theprocessor system can include a modeling module, an input module and aplanning module. The modeling module may be configured for identifying athree dimensional boundary surface between the blood vessel and bloodflowing therein from the image data. The modeling module can beconfigured for transmitting three dimensional model data to the display.The input module may receive user input data relative to the threedimensional model so as to identify a radiation target offset from theblood/vessel boundary surface. The planning module may be configured forplanning a pattern of ionizing radiation treatment beams in response tothe radiation target so as to reduce nerve activity within the nerve andto limit radiation along the blood/vessel boundary.

In some embodiments the image capture device may acquire image data froma blood vessel adjacent to the renal plexus. In certain embodiments, theplanning module may be configured to plan the irradiation treatment soas to provide a decreasing dose between the target and the blood/vesselboundary. The image capture device may acquire image data from an aortaor a renal artery. The input module may receive user input data of aradiation target which is offset a distance within a range from about0.25 mm to about 6 mm from the blood/vessel boundary surface. Further,the radiation target's offset distance may vary longitudinally along theboundary within a range from about 0.5 mm and 3.0 mm.

In further embodiments of the system, the planning module may beconfigured to output the ionizing radiation treatment plan fordenervation of the adjacent nerve to a plurality of slices of twodimensional image data. A system may receive user input on the displayand the display may facilitate the input by snapping the input of theionizing radiation target relative to a location on the threedimensional model. The three dimensional model data may comprise asurface radially offset from the identified blood/vessel boundarysurface and the display may facilitate the input by snapping the inputof the radiation target onto the surface of the three dimensional model.

In certain embodiments of the system, the planning module is furtherconfigured to expand a treatment pattern of intersecting radiation beamsalong a longitudinal axis of the blood/vessel boundary surface such thatrenal nerve activity is reduced so as to treat hypertension. Theplanning module may be configured to generate an ionizing radiationtreatment plan based upon the user input and may project a dose cloud tothe three dimensional model based upon the treatment pattern so as toverify the dose of radiation along the blood/vessel boundary issufficiently low to inhibit hyperplasia. The radiation target mayinclude one or more annual circumferential segments. The image capturedevice may acquire image data from a blood vessel adjacent to one of aceliac ganglion, a superior mesenteric ganglion, an aorticorenalganglion, nerves in the renal ostium region, and nerves in the renalartery branching region.

In some embodiments, a non-transitory computer readable medium withcomputer executable instruction stored thereon for developing aradiosurgical renal denervation treatment plan is provided. The computerreadable medium may include instructions for acquiring image data from ablood vessel adjacent to a nerve. The computer readable mediuminstructions may generate a three dimensional model by identifying aboundary surface between the blood vessel and blood flowing therein fromthe image data. Input regarding a radiation target with reference to animage of the three dimensional model may be received. The receivedradiation target input may be offset from the blood/vessel boundarysurface. An irradiation treatment of the radiation target may be plannedso as to provide a neural function-altering dose of radiation at thetarget and a safe luminal dose of radiation at the blood/vesselboundary. A ionizing radiation treatment plan may optionally begenerated based on the user input and a dose cloud may be projected onthe three dimensional model based on the treatment plan if desired. Insome embodiments, the surface may be a layer between the epithelial celllayer and the outer edge of the blood vessel adventitia. In certainembodiments, the dose cloud may be evaluated to ensure the safe luminaldose of radiation at the blood/vessel boundary.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B illustrate portions of the renovascular structure to whichembodiments of the present invention may be applicable;

FIG. 2 is a flowchart representing a method of radiosurgical treatmentaccording to the embodiments;

FIG. 3 illustrates an exemplary modified stereotactic radiosurgerysystem that may be utilized with embodiments;

FIG. 4 is a flowchart broadly describing treatment planning according toembodiments of the present invention;

FIGS. 5A-5C depict exemplary target treatment regions with reference toanatomical structure according to an exemplary embodiment of the presentinvention;

FIG. 6 is a block diagram of a computer system that may be utilized withembodiments herein;

FIG. 7 schematically illustrates a plurality of modules that may carryout embodiments of the present invention;

FIG. 8 is a flow chart representing a method of generating a threedimensional model of a surface of interest in accordance with anembodiment;

FIG. 9 is a flow chart representing a method for preparing a treatmentplan utilizing the model of the surface generating in FIG. 8 inaccordance with an embodiment;

FIGS. 10A-10B depict a representation of three-dimensional surfaces forreceiving input. FIG. 10A is a representation of a blood/vessel boundarysurface and FIG. 10B is an estimated target location surface inaccordance with FIG. 8;

FIG. 11 is a representation of a cardinal plane of the blood vesseladjacent to the target nerves for which the surface of FIGS. 10A-10B hasbeen generated, showing intersection points of the treatment lines ofFIGS. 10A-10B;

FIGS. 12A-12B is a representation of the expansion of the treatmentlines in FIGS. 10A-10B into volumes in accordance with an embodiment;

FIG. 13 is a representation of a cardinal plane of the blood vesseladjacent to the target nerves for which the surface of FIGS. 10A-10B hasbeen generated, showing the intersection area of the volumes of FIGS.12A-12B;

FIG. 14 is an axial slice of a portion of the renovascular system with aplanning target volume projected thereon in accordance with anembodiment;

FIG. 15 is a representation of a three dimensional model of a portion ofthe renovascular system , with a treatment plan added on a left view anda dose cloud added on a right view, in accordance with embodimentsherein;

FIG. 16 is a flow chart representing a method of evaluating a dose cloudwith respect to the blood/vessel boundary surface in accordance with anembodiment;

FIG. 17 shows a dose cloud projected relative to the generated surfacealong with the treatment lines in accordance with an embodiment;

FIGS. 18A-18E is an axial slice of a generated surface of FIG. 15 withthe dose cloud and the treatment lines shown thereon;

FIG. 19 is a flow chart representing a method of determining if a dosecloud is acceptable in accordance with an embodiment; and

FIG. 20 shows a surface patch indicating radiation dosage coverage on agenerated tissue surface in accordance with an embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally provides improved devices, systems, andmethods for planning radiosurgical treatments for neuromodulating aportion of the renovascular system. The embodiments herein may be usedto plan radiosurgical neuromodulation treatments for conditions ordisease associated with elevated central sympathetic drive, includingrenovascular hypertension, heart failure, chronic kidney disease,insulin resistance, diabetes, metabolic syndrome, sleep apnea, atrialfibrillation, and/or dyspnea. Additionally, embodiments of the presentinvention detailed herein and variations thereof may be used to planradiosurgical renal neuromodulation of various target regions. The renalnerves may be located and targeted at the level of the ganglion and/orat postganglionic positions, as well as preganglionic positions. Targetregions include the renal plexus, celiac ganglion, the superiormesenteric ganglion, the aorticorenal ganglion and the aortic plexus.

It should be understood that reference to the singular, as in a renalartery, renal nerves about a renal artery, kidney, etc., encompassesboth the singular and plural, and vice versa. It is further to beunderstood that while embodiments may be described herein with referenceto renal nerves, the teachings herein and variations thereof may also beapplicable to the renal ganglia and/or the aortic renal ganglia ingeneral. Indeed, the teachings herein and variations thereof areapplicable to a wide variety of devices, systems and/or methods thatutilize ionizing radiation to partially or completely block neurologicalcommunication between one or both kidneys of a patient and a patient'scentral nervous system, thereby reducing hypertension or the like,including robotic radiosurgical systems, gantry-type radiosurgicalsystems, and the like. Thus, while preferred embodiments have beendescribed, the details may be changed without departing from theinvention, which is defined by the claims.

FIG. 1A illustrates a portion of the renovascular structure 2. As may beseen in FIG. 1A, the kidney 4 is innervated by the renal plexus (RP) 6,which is intimately associated with the renal artery 8. The renal plexus6 is an autonomic plexus that surrounds the renal artery 8 and isembedded within or adjacent to the adventitia of the renal artery 8. Therenal plexus 6 extends along the renal artery 8 until it arrives at thesubstance of the kidney 4. Fibers contributing to the renal plexus 6arise from the celiac ganglion 10, the superior mesenteric ganglion 12,the aorticorenal ganglion 14 and the aortic plexus. The renal plexus 6,also referred to as the renal nerve or nerves, is predominantlycomprised of sympathetic components. There is no (or at least verylittle) parasympathetic innervation of the kidney 4. FIG. 1B depicts aconceptual unscaled cross-sectional view of the renal artery 8 and renalnerves 6. The renal nerves 6 are surrounded by membrane 16 located inperiarterial space 18. The boundary of membrane 20 is conceptuallydepicted. In an exemplary embodiment of the present invention, theionizing radiation treatment plan at least provides radiation dosessufficient to reduce neural activity by partially enveloping renalnerves 6.

FIG. 2 provides an exemplary flow chart 22 which represents a methodused for radiosurgical treatment according to embodiments of the presentinvention. The target tissues are first imaged 24 by a medical imagingmodality, and then a plan 26 can be prepared for treatment of the tissueat the target site. After completion of plan 26, radiosurgical treatment28 of the renal nerve may be initiated according to plan 26.

The internal tissues are imaged 24 for planning purposes, typicallyusing a remote imaging modality such as a computed tomography (CT),magnetic resonance imaging (MRI), ultrasound imaging, X-ray imaging,optical coherence tomography, a combination of these, or other imagingmodalities. Note that the tissue structure which will actually betargeted for radiation remodeling need not necessarily be visible in theimage, for example, when sufficiently contrasting surrogate structuresare visible in the image data to identify the target tissue location.The imaging used in many embodiments will include a time sequence ofthree-dimensional tissue volumes, with the time sequence typicallyspanning one or more movement cycles (such as a cardiac or heartbeatcycle, a respiration or breathing cycle, and/or the like). In exemplaryembodiments, the image data comprises a series of CT slices through ablood vessel adjacent to the target renal nerve so as to providevolumetric or three-dimensional image data. The time series ofthree-dimensional blood vessel images are preferably acquired at timesthat are distributed throughout the heartbeat cycle so that the imageplanning data effectively comprises a time series of three-dimensionalimage datasets providing information regarding the motion of the bloodvessel tissues during the cardiac cycle.

Based on the imaging data obtained from imaging 24, a plan 26 can beprepared for treatment of the tissue at the target site. Embodimentsherein are directed to systems and methods that aid in development ofplan 26 which may be used with existing or newly developed imaging 24and treatment 28. One advantage of the plan 26 defined herein is that itmay be used with existing imaging, such as the CT imaging describedabove, and with conventional radiosurgical planning tools, such as theMULTIPLAN planning tool (Accuray, Inc.). Imaging, for example, may takethe forms described above or other forms. In exemplary embodiments aconventional series of image slices (e.g. CT slices) through a bloodvessel adjacent to the renal nerve is utilized so as to providevolumetric or three-dimensional image data. Treatment 28 may beconventional or modified, and one embodiment is described inconcurrently filed U.S. patent application Ser. No. 61/483,962 entitled,“Renovascular Treatment Device, System, and Method for RadiosurgicallyAlleviating Hypertension” (Attorney Docket No. 88587-782065), the fulldisclosure of which is incorporated herein by reference.

Treatment plan 26 typically comprises a target region and a series ofradiation beams which intersect within the target region. The radiationdose within the target tissue should be at least sufficient to providethe desired lesions or renal neuromodulation. For example, the radiationdose may comprise ablative or sub-ablative doses of ionizing radiation.The dose will be sufficient to inhibit or reduce sympathetic activity ofthe renal nerve. Radiation dosages outside the target tissue willpreferably decrease with a relatively steep gradient so as to inhibitexcessive damage to collateral tissues, with radiation dosages inspecified sensitive and/or critical tissue structures often beingmaintained below a desired maximum threshold to avoid deleterious sideeffects. For example, treatment plan 26 may be configured or adjusted tominimize radiation exposure at the endothelium. Further, radiationexposure at the blood vessel lumen may be minimized so as to minimizethe chances of blood occlusion within the blood vessel adjacent to thetarget nerve.

Treatment 28 may utilize known radiation delivery systems to treat apatient according to plan 26. As an example, an exemplary modifiedCYBERKNIFE stereotactic radiosurgery system 30 is illustrated in FIG. 3.Radiosurgery system 30 includes a lightweight linear accelerator 32mounted to a robotic arm 34. An image guidance system 36 includesbiplane diagnostic X-ray sources 38 and image detectors 40 so as toenhance registration between robot arm 34 and the target site. As thetissues in the target region may not present a high-contrast image,image guidance system 36 may use image processing techniques to identifythe location of one or more surrogate structures, with the surrogatestypically including a high-contrast natural tissue structure (such as abone or the like) or an artificial implanted fiducial marker that movesin correlation with the target tissue. Target tracking may also makesure of one or more surface image cameras 42, particularly foridentifying pulsatile movement of blood vessels adjacent to renalnerves. Cameras 42 may monitor high-contrast fiducial markers placedrelative to the target nerve. A patient support 44 is moveably supportedby an alignment arm 46 so as to facilitate bringing the patient (andtreatment site) into alignment with robot arm 34.

Referring now to FIGS. 4 and 5A, FIG. 4 describes an exemplary planningflowchart 48 and FIG. 5A illustrates portions of the exemplary planningprocess. A modeling module generates 50 a three dimensional model of asurface 60, generally from CT slices of a blood vessel adjacent to atarget nerve, although other imaging data may be used. In the exampleshown in the drawings, the surface 60 is of a portion of therenovascular system. A user interface or input module allows the systemuser to input 52 a desired radiation treatment pattern 62 with referenceto the model. The desired radiation treatment pattern 62 is at an offsetdistance from the blood/tissue boundary of a blood vessel adjacent tothe radiation target. The offset distance allows a neuralfunction-altering dose of radiation at the radiation target and a safeluminal dose of radiation at the adjacent blood/vessel boundary.

At 54, the series of boundaries generated by the desired radiationpattern 62 may be projected back onto the individual CT scan slices,which then may be transferred to a conventional radiosurgical planningtool. Thus, the input to the conventional radiosurgical tools isgenerally the same as the input in prior methods (i.e. boundariesdefined on individual CT scan slices). However, as described in thebackground of this disclosure, prior methods required a surgeon to drawon each individual slice. In contrast, methods and systems hereingenerate the desired treatment pattern 62 relative to the threedimensional model of the surface 60.

In some embodiments, as described below, a visualization of a dose cloud64 and 66 (FIG. 5B-5C) may be provided for displaying on the surface 60.The dose cloud 64 in FIG. 5B depicts, in a quasi-three dimensionalmanner, the outer boundaries of a 20 Gy dose cloud. Dose cloud 66 inFIG. 5C illustrates the outer boundaries of a 10 Gy dose cloud. The dosecloud may be received 56 as an output treatment indication by aconventional radiosurgical tool and, in accordance with embodiments, maybe displayed 58, for example, as an isodose contour on the surface 60.As with the desired treatment pattern 62, the dose cloud 64 and 66 maybe used in part of generating or approving the plan 26 (FIG. 2).

To generate a surface 60 if the blood/vessel boundary surface of a bloodvessel adjacent to a target nerve, a modeling module may be configuredfor identifying a three dimensional boundary surface between a bloodvessel and blood flowing therein from the image data. An image contrastagent may be introduced during the image acquisition step 24 so that theinner surface of the blood vessel may be more easily identified from theimage data. Thus, there is a clear demarcation between the tissue andthe blood, allowing for a more precise definition of the blood/vesselboundary surface 60.

For example, if the target nerves include the renal plexus, the modelingmodule may identify the boundary surface between the renal artery andthe blood. A model of the blood/vessel boundary surface of the renalartery may then be used for planning a radiosurgical treatment of therenal plexus. Although the surface has been described as theblood/tissue interface of the renal artery adjacent to the renal plexus,it will be appreciated that this example is illustrative and variationsand modifications are possible. For instance, surface 60 may be theblood/tissue interface of other blood vessels adjacent to otherrenovascular nerves. Alternative embodiments may employ a surfaceradially offset a distance from the identified blood/tissue boundary.The offset distance may correspond to an estimated location of thetarget nerve. For example, the renal nerves may be offset from theblood/tissue boundary of the renal artery at a range from about 0.25 mmto about 6 mm. An embodiment may provide a surface radially offset 2 mmfrom the blood/tissue boundary of the renal artery as an estimate of arenal nerve target location. Further, the offset distance from theidentified blood/tissue boundary surface may vary longitudinally alongthe boundary. Other nerve targets may range at an offset distance fromabout 0.5 mm to about 3.0 mm.

Embodiments herein may utilize computer-implemented methods forgenerating the three dimensional surface 50, indicating a desiredtreatment pattern 52, providing the dose cloud 56, and/or operate themethods or functions of the systems described herein. To this end, FIG.6 is a simplified block diagram of an exemplary computer system 68 thatmay be utilized in embodiments described herein. The computer system 68typically includes at least one processor 70 which communicates with anumber of peripheral devices via a bus subsystem 72. These peripheraldevices may include a storage subsystem 74, comprising a memorysubsystem 76 and a file storage subsystem 78, user interface inputdevices 80, user interface output devices 82, and a network interfacesubsystem 84. Network interface subsystem 84 provides an interface to acommunication network 86 for communication with other imaging devices,databases, or the like.

The processor 70 performs the operations of the computer system 68 usingexecution instructions stored in the memory subsystem 76 in conjunctionwith any data input from an operator. Such data can, for example, beinput through user interface input devices 80, such as the graphicaluser interface. Thus, processor 70 can include an execution area intowhich execution instructions are loaded from memory. These executioninstructions will then cause processor 70 to send commands to thecomputer system 68. Although described as a “processor” in thisdisclosure, the functions of the processor may be performed by multipleprocessors in one computer or distributed over several computers.

User interface input devices 80 may include a keyboard, pointing devicessuch as a mouse, trackball, touch pad, or graphics tablet, a scanner,foot pedals, a joy stick, a touchscreen incorporated into the display,audio input devices such as voice recognition systems, microphones, andother types of input devices. In general, use of the term “input device”is intended to include a variety of conventional and proprietary devicesand ways to input information into the computer system 68. Such inputdevices will often be used to download a computer executable code from acomputer network or a tangible storage media embodying steps orprogramming instructions for any of the methods of the presentinvention.

User interface output devices 82 may include a display subsystem, aprinter, a fax machine, or non-visual displays such as audio outputdevices. The display subsystem may be a cathode ray tube (CRT), aflat-panel device such as a liquid crystal display (LCD), a projectiondevice, or the like. The display subsystem may also provide non-visualdisplay such as via audio output devices. In general, use of the term“output device” is intended to include a variety of conventional andproprietary devices and ways to output information from the computersystem to a user.

Storage subsystem 74 stores the basic programming and data constructsthat provide the functionality of the various embodiments. For example,database and modules implement the functionality of embodimentsdescribed herein may be stored in storage subsystem 74. These softwaremodules are generally executed by processor 70. In a distributedenvironment, the software modules may be stored in a memory or aplurality of computer systems and executed by processors of theplurality of computer systems and executed by processors of theplurality of computer systems. Storage subsystem 74 typically comprisesmemory subsystems 76 and file storage subsystem 78.

Memory subsystems 76 typically includes a number of memories including aread only memory (ROM) 88 in which fixed instructions are stored andmain random access memory (RAM) 90 for storage of instructions and dataduring program execution. File storage subsystem 78 provides persistent(non-volatile) storage for program and data files, and may include ahard disk drive, a floppy disk drive along with associated removablemedia, a Compact Digital Read Only Memory (CD-ROM) drive, an opticaldrive, DVD, CD-R, CD-RW, or removable media cartridges or disks. One ormore of the drives may be located at remote locations on other connectedcomputers at other sites coupled to the computer system. The databasesand modules implementing the functionality of the present invention mayalso be stored by file storage subsystem 78.

Bus subsystem 72 provides a mechanism for letting the various componentsand subsystems of the computer system communicate with each other asintended. The various subsystems and components of the computer systemneed not be at the same physical location but may be distributed atvarious locations within a distributed network. Although bus subsystem72 is shown schematically as a single bus, alternate embodiments of thebus subsystem may utilize multiple buses.

The computer system 68 itself can be of varying types include a personalcomputer, a portable computer, a workstation, a computer terminal, anetwork computer, a module in a display unit, a mainframe, or any otherdata processing system. Due to the ever-changing nature of computers andnetworks, the description of the computer system 68 depicted in FIG. 6is intended only as a specific example for purposes of illustrating oneembodiment of the present invention. Many other configurations of thecomputer system are possible having more or fewer components than thecomputer system 68 depicted in FIG. 6.

FIG. 7 schematically illustrates a plurality of modules 92 that maycarry out embodiments of the present invention. The modules 92 may besoftware modules, hardware modules or a combination thereof. If themodules 92 are software modules, the modules will be embodied on acomputer readable medium and processed by processor 70.

A digital data module 94 receives CT volume or other diagnostic imagesand, if not already digitized, creates a digital data file of theimages. A 3-D modeling module 96 builds a finite element or solid modelof the desired surface from the digital data file. Such 3-D modelingmodules are known, and example implementation details are providedbelow, along with a description of FIG. 8. However, briefly described,the 3-D modeling module 96 process the slices of the CT volume andcreates a finite element or solid model of the surface of interest,projected as the surface 60 (FIGS. 5A-5C) For ease of reference, as usedfrom this point forward, the “surface 60” refers to the 3-D model of thesurface of interest. As set forth above, surface 60 may be in theblood/tissue boundary of a blood vessel adjacent to a renovascularnerve. Further, surface 60 may be a radially offset distance from theblood/tissue boundary so as to provide an estimated nerve targetlocation.

The surface 60 may be shown, for example on a display for the computingdevice 68, and may be manipulated by a user, for example via the userinterface input device 80 so as to see a desired orientation, crosssection, or other desired view. Panning and yaw and pitch movement maybe provided as well.

A planning module 98 permits a user of the system to generate thetreatment plan 62 (FIG. 5A). The planning module 98 may also project thetreatment plan back onto the CT slices.

A dose cloud module 100 may receive or generate the dose cloud 64 and66. An example implementation of the dose cloud module 100 is set forthbelow, for example with the discussions of FIGS. 16 and 19.

The dose cloud module 100 and the 3-D modeling module 96 may be utilizedwith a standard treatment planning module 102. An example of such atreatment planning module is the MULTIPLAN treatment module, althoughother treatment modules may be used.

FIG. 8 is a flowchart representing a method of generating a surface ofinterest, e.g., the surface 60, in accordance with an embodiment. At104, the information regarding the CT volume is input, for example viathe module 94. This input may be, for example, a CT volume generated toaccentuate the tissue-blood boundary information provided for each CTslice. In the examples described herein, the tissue-blood boundary isthe boundary between the blood and the inner surface a blood vesseladjacent to a renovascular nerve and that boundary is accentuated by,for example, adding a contrasting agent to the blood. The boundarybetween the blood (including the added contrast) and the blood vesseltissue in each slice of the CT data can be segmented in one, some, orall of the volumetric data sets associated with the cardiac cyclephases. The segmented regions can be stacked or assembled together toform the surface 60.

At 106 to 112, examples are provided of smoothing techniques that may beapplied between the boundaries of the slices so as to generate a 3-Dsurface, such as surface 60. Other smoothing techniques may be used.Smoothing may be performed, for example, via the module 96.

At 106, Voxel editing occurs, in which the CT volume is converted to agrid of blocks in three dimensional space. At 108 (optional),connectivity occurs. At 110, surface generation occurs, for exampleutilizing the Marching Cubes computer graphics algorithm , whichproceeds through the voxels, taking eight neighbor locations at a time(thus forming an imaginary cube), then determining the polygon(s) neededto represent the part of the isosurface that passes through the cube.The individual polygons are then fused into the desired surface.

At 114, the desired surface is output, for example as shown as thesurface 60 in FIG. 10A. For the example herein, the surface 60represents a blood/tissue boundary of a blood vessel adjacent to a nerveof the renovascular system. The entire process in FIG. 8 may beautomated using a segmentation scheme.

FIG. 9 is a flow chart representing a method for preparing a treatmentplan utilizing the surface 60 generated in FIG. 8. Beginning at 116,desired treatment pattern 130 a and 130 b (FIG. 10A) corresponding to aradiation target are received with reference to the surface 60. Forrenal neuromodulation the radiation target comprises the nerves adjacentto the blood vessel. The nerves are offset a distance from theblood/tissue boundary of the blood vessel. Thus the radiation target anddesired treatment pattern lines 130 a and 130 b are offset a distance132 from surface 60 so as to provide a neural function altering dose ofradiation at the nerves and a safe luminal dose of radiation at theblood/vessel boundary. As shown in FIG. 10A, desired treatment patternline 130 a is offset distance fixed distance 132 a from surface 60.However, treatment pattern line 130 b is offset a different distance 132b and 132 c from surface 60. Thus it should be understood that offsetdistance 132 may vary for desired treatment patterns 130 and may evenvary for individual treatment patterns 130, e.g. treatment pattern 130 bis offset a distance which varies from offset distance 132 b and 132 c.

In the alternative embodiment shown in FIG. 10B, the treatment plan maybe prepared utilizing a surface 60 which is offset a distance 138 fromblood/vessel boundary surface 134. The offset distance 138 from theblood/vessel boundary may correspond to a location of the adjacenttarget nerves. Thus the offset surface 60 may correspond to an estimatedlocation of the target nerves. The modeling module may identify theblood/vessel boundary surface 134 and surface 60 may be generated byoffsetting a distance 138 from the blood/vessel boundary surface 134.Similar to above, the offset distance 138 may vary radially andlongitudinally along the blood/vessel boundary 134. The desiredtreatment patterns 136 a and 136 b may then be received with referenceto the surface 60. The treatment patterns 136 are similarly configuredto provide a neural function altering dose of radiation at the adjacentnerve and a safe luminal dose of radiation at the blood/vessel boundary.

These desired treatment lines 130 may be snapped and extended at anoffset distance 132 from the exterior of the surface 60. Alternatively,the desired treatment lines 136 may be snapped directly to and extendedalong the exterior of surface 60. For example a physician may utilizethe user interface input device 80 to input a desired treatment pattern.In an example, a physician may click along the surface and the desiredtreatment pattern lines may extend as a straight line between clicks. Inthe embodiment in 10A, the desired treatment lines 130 extend at adesired offset distance from the surface. In the embodiment of 10B, thedesired treatment lines 136 extend along the exterior of surface 60.Smoothing may be enabled. If desired, the surface 60 may be rotated,panned, and zoomed on the screen, or the pitch or yaw may be altered, soas to allow the physician to access a desired view of the surface toproperly orient the treatment lines 130. Such manipulation features areknown in existing 3-D modeling and display software.

Applying the treatment lines 130 and 136 via the user interface inputdevice 80 allows the planning medical professional to input anappropriate treatment pattern as a series of lines or curves relative tothe three dimensional model surface 60. The treatment lines 130 and 136may be applied as a very thin line or as a thickness that is defined bythe system or user. In accordance with an embodiment, the treatmentlines are displayed at a width that is sufficient to reduce neuralactivity in across the treatment line. Using such a width providesintuitive visual feedback to a user of the system, so that the user mayhave a more realistic idea of the location and breadth of a lesionpattern.

If desired, at 118 the treatment lines may be shown in one or morecardinal planes. As an example, as is shown in FIG. 11, a cardinal planof the renal artery 8 for which surface 60 was generated showsintersection line 140. The intersection line 140 represents the crosssection of the treatment lines 130 and 136 at the given cardinal plane.As can be seen, the intersection line 140 is an offset distance 132 fromthe blood/vessel boundary surface 134. Further, the intersection line140 is located within a region of the renal nerves 6. Other cardinalplanes may be displayed either simultaneously on the display or bytoggling between a view of the surface 60 and the cardinal plane. Thecardinal planes may represent, for example, data from a single CT slice.

At 120, the desired treatment lines 130 and 136 are expanded to volumesso as to provide the desired therapeutic benefit at the adjacent nerves,and may be visualized on the display in three dimensions, FIGS. 12A-12B.118 may occur after 120 and indeed, unless stated otherwise herein, theacts set forth in the flowcharts of this disclosure are not limited tothe order in which they are presented. To visualize the volume in threedimensions, the treatment lines 130 and 136 may be given a threedimensional thickness by generating loops having a radius around thetreatment pattern lines 130 and 136. Since the offset distancecorresponds to a distance from the blood/vessel boundary surface, theradius should be less than the offset distance so as to provide a neuralfunction altering dose of radiation at the target and a safe luminaldose of radiation at the blood/vessel boundary. The radius may beapplied around the treatment pattern lines, or separate width and lengthradii may be used. In an example, volumes may be generated utilizing aradius of 0.5 mm, but other radii may be used. The expansion ofintersection line 140 (FIG. 11) to a volume is depicted in the cardinalplane in FIG. 13. FIG. 13 shows the cardinal plane of the blood vesseladjacent to the target nerves. The expansion of intersection line 140(FIG. 11) to a treatment volume creates an intersection area 141indicative of the treatment volume intersection at this cardinal plane.

In an embodiment the volumes enclose a portion of the nerves adjacent tothe blood vessel and define a planning target volume (PTV) for treatmentplanning purposes. The PTV represents the area of tissue of interest atwhich treatment is desirably to occur. In the example of the renalartery, the PTV is preferably a portion of the renal plexus, and maycomprise one or more annular circumferential segments. The PTV shouldalso be limited at the blood/vessel boundary surface 134 so as toprovide a safe luminal dose of radiation at the blood/vessel boundary toinhibit hyperplasia.

At 122, the PTV is scan converted to generate contours in each of thecardinal planes. Existing radiosurgical radiation beam calculatingmodules may be used to determine the resulting radiation contourdistribution. Existing radiosurgical planning approaches foridentification of radiation sensitive structures may be implemented. Theinput to such existing calculating modules may require input via slices,such as conventional CT slices. Thus, if such calculating modules areused, the CT slices are utilized to generate the solid volume (FIG. 8),the plan is formed on the solid volume (FIG. 9), and then the plan ateach slice is provided back to the calculating module to generate thecontours. Thus, the output 124 may be an output relative to each of theoriginal CT slices. An example of an axial slice of the contours 142 isshown in FIG. 14.

Alternatively, the treatment pattern lines 130 or 136 may be definedusing a cardiac and/or respiratory gated 4 DCT data set. Suppose there N(typically N=10) volumes of CT data acquired over time. A blood/vesselsurface (e.g., the surface 60) will be constructed from each CT volume,resulting in N such surfaces. Using each surface, a set of treatmentlines will be defined by the user, resulting in N such treatment lines.This time-varying treatment lines and the time-varying CT data will thenbe imported to a treatment planning station line treatment planningmodule, e.g., MULTIPLAN, for generating a treatment plan. Alternatively,one treatment pattern line set, whose volume will include the volumesfrom all individual treatment pattern lines, can be generated and usedfor planning

In accordance with an embodiment, placement of the treatment patternlines on a surface may be partially or fully automated. A template ofpossible treatment pattern lines may be provided to the user, and theuser may then drag and drop the selected template at a proper locationon the surface. The user may modify the treatment line locally by movingit around on the surface. The thickness may also be changed.

The contours 142 may be saved, for example, as DICOM RTSS (RadiationTherapy Structure Sets) files. The planner to which they are output maybe, for example, MULTIPLAN. In an embodiment, evaluation is done usingPTV. Optimizing the plan based on the PTV is preferred because focus ison the actual area in which treatment is desired.

In another embodiment, instead of transmitting the treatment patternlines as 2D contours in cardinal planes or oblique planes to a planningmodule, the treatment pattern lines may be transmitted as 3D shapes tothe planning module.

Along with inputting a desired treatment pattern 62, as schematicallyillustrated in FIG. 5A, the planning module and user interface willpreferably output an estimate of the actual radiation exposure relativeto the blood/vessel surface, preferably in the form of an estimatedtissue exposure 144 (FIG. 15). Estimated exposure 144 may represent theportion of tissue relative to surface 60 which receives a radiation doseabove a necrotic threshold, optionally based on radiation beams andradiation dose output from an existing radiosurgical treatment planner.Alternative patterns may represent an estimate of tissue which willreceive a sufficient dose of radiation for therapeutic remodeling so asto reduce the sympathetic activity of the adjacent nerve. The user mayinteractively develop the plan based on iterative input into and outputfrom the planning treatment module 102.

Ideally, the dose cloud should correspond to the treatment lines. FIG.16 is a flow chart representing a method of evaluating a dose cloud withrespect to the generated surface 60 in accordance with an embodiment. At146, the dose cloud is generated and is overlaid relative to the surface60 at 148. If desired, the treatment lines 130 or 136 are displayedrelative to the surface 60 at 150.

As shown in FIG. 17, displaying the treatment lines 130 and a dose cloud154 relative to the surface 60 allows a visual inspection of whether thedose cloud is covering the target intended by the physician. To thisend, at 152, the physician may visually evaluate whether the dose cloudis covering the target. As can be seen in FIG. 17, for at least the viewshown in the drawing, the dose cloud 154 provides a safe radiationluminal dose of radiation at the blood/vessel boundary. Rotation,panning, or zooming of the surface, or adjustment of the pitch and/oryaw, may be required for a full inspection of dosage coverage.

The dose cloud 154 may represent, for example, all dose values that aregreater than a particular threshold or, as an alternative, dose valueslying in a range between a minimum and a maximum. If desired, as shownin FIG. 18A-18E, an axial slice of each cardinal plane may be provided,with the isodose lines 156 and inner most contour 142 shown thereon.This representation permits a physician to look at each slice to ensurethat the dose is covering (e.g., surrounding) the target adequatelywhile the blood/vessel boundary receives a safe luminal dose ofradiation. Starting in order from the innermost to the outermost isodoseline, after the contours corresponding to target 142, the points on theinnermost isodose 156 a correspond to an absorbed dose of 30 Gy ofradiation, and the points inside of isodose 156a receive an absorbeddose of at least 30 Gy of radiation. The points on the next innermostisodose 156 b correspond to an absorbed dose of 20 Gy of radiation, andthe points inside of isodose 156 b receive an absorbed dose of at least20 Gy of radiation. The points on the next innermost isodose 156 ccorrespond to an absorbed dose of 10 Gy of radiation, and the pointsinside of isodose 156 c receive an absorbed dose of at least 10 Gy ofradiation. The points on outer isodose 156 d correspond to an absorbeddose of 5 Gy of radiation, and the points inside of isodose 156 dreceive an absorbed dose of at least 5 Gy of radiation. It is noted thatpoints within box 157 receive less than 5 Gy of radiation. However, itis noted that there may be areas outside a given isodose/box 157 and/orinside a given isodose/box 157 where the predicted absorbed dose isdifferent than specified. By way of example, there may be areas near theskin that experience a dose flare and/or areas inside the isodose linesthat experience a dose deficiency. The size of the elements of thesefigures is scaled to the anatomy of an average male adult. Along theselines, it can be seen that embodiments of the present invention resultin inhomogeneous radiation delivery that delivers more than about 15 Gywithin 4 mm of the outer wall of the renal arteries. It is noted thatwhile a unilateral treatment has been depicted with respect to FIGS.18A-18E, the data presented with respect to these figures is applicableto a bilateral treatment as well, and the opposite renovascularstructure from that depicted in the FIGS. would substantially correspondto that depicted in the FIGS.

FIG. 19 is a flow chart representing a method of determining if a doseis sufficient in accordance with an alternate embodiment. The method inFIG. 19 involves clipping a dose cloud relative to a surface 170 (FIG.20), and may be used in addition to, or instead of the visual inspectiondescribed above, where the dose cloud is represented more as a contour.At 158, the region corresponding to the acceptable dose value is clippedrelative to a surface 170. The dose values may be represented in isodosefashion, with different doses being displayed in different ways, forexample as different colors. Alternatively, as in the previousembodiment, all doses exceeding a value or falling in a range may bedisplayed.

By clipping the dose value relative to a surface, the dose is presentedas a curved surface patches 172 a and 172 b (FIG. 20) on the surface170. A physician may visually evaluate the surface patch 172 a withrespect to the target tissue to determine whether the target tissuereceives a neural function altering dose of radiation while the adjacenttissue is exposed to acceptable doses of radiation 172 b. For example,the surface patch 172 a may be evaluated to determine whether it is wideenough to reduce neural activity in the tissues being treated.

In addition, the physician may evaluate the surface patch 172 a todetermine whether the surface patch 172 a provides a safe luminal doseof radiation at the blood/vessel boundary surface at 160. If there areany radiation doses at the blood/tissue boundary surface which couldprompt hyperplasia or within the blood vessel walls which could occludethe blood in the blood vessel, a reduction in hypertension may not beprovided by the radiological treatment. To this end, at 162, thephysician evaluates whether the surface patch 172 a is offset asufficient distance from the blood/tissue boundary surface, such thathyperplasia and blood occlusion may be inhibited. If not, an error maybe generated at 164 either by software or a recognition by the user,causing the physician to construct a new plan or causing the computersystem 68 to generate an error message, or to be handled in anothermanner. If the surface patch 172 a is a sufficient offset distance fromthe blood/tissue boundary surface, then the physician may proceed totreatment at 168.

The physician and/or the computer system 68 may rotate and otherwisemanipulate the surface 170 so that the physician may fully inspect thesurface patch 172 a. In an alternate embodiment, software may walkacross the surface patch 172 a to confirm that the surface patch remainsa certain offset distance from the blood/tissue boundary surface. Thissame software or visual inspection may be used to determine whether thesurface patch 172 a is sufficiently wide to reduce neural activity inthe adjacent nerves. For example, the software may crawl around thesurface 172 a and evaluate a pixel width of the surface patch 172 a. Ifthe pixel width falls below a threshold, an error may be generated.

Any effects of possible misalignment errors (x, y, z translation androll, pitch, yaw, rotation errors) during treatment may be evaluatedwith this system. The surface 170 or the CT data set may be translatedand rotated in relation to the dose cloud to understand the effect ofany misalignment on the necessary offset distance between the radiationdose and the blood/vessel boundary surface. Alternatively the dose cloudmay be translated or rotated in relation to the surface or the CT dataset.

After the contours are approved, the plan 26 is complete, and may beimplemented. Radiosurgical treatment of the nerves may be initiated, forexample, by positioning the patient on patient support 44, bringing thepatient into alignment with robot arm 34, and directing the plannedseries of radiation beams from the linear accelerator 32 to the targetregion of the renovascular system.

Other variations are within the spirit of the present invention. Thus,while the invention is susceptible to various modifications andalternative constructions, certain illustrated embodiments thereof areshown in the drawings and have been described above in detail. It shouldbe understood, however, that there is no intention to limit theinvention to the specific form or forms disclosed, but on the contrary,the intention is to cover all modifications, alternative constructions,and equivalents falling within the spirit and scope of the invention, asdefined in the appended claims.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising,” “having,” “including,” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. The term “connected” is to beconstrued as partly or wholly contained within, attached to, or joinedtogether, even if there is something intervening. Recitation of rangesof values herein are merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range,unless otherwise indicated herein, and each separate value isincorporated into the specification as if it were individually recitedherein. All methods described herein can be performed in any suitableorder unless otherwise indicated herein or otherwise clearlycontradicted by context. The use of any and all examples, or exemplarylanguage (e.g., “such as”) provided herein, is intended merely to betterilluminate embodiments of the invention and does not pose a limitationon the scope of the invention unless otherwise claimed. No language inthe specification should be construed as indicating any non-claimedelement as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

1. A radiosurgical method for altering neural function of a patientbody, the method comprising: acquiring image data from a blood vesseladjacent to a nerve; generating a three dimensional model by identifyinga boundary between the blood vessel and blood flowing therein from theimage data; receiving input regarding a radiation target with referenceto an image of the three dimensional model, wherein the target is offsetfrom the blood/vessel boundary surface; and planning an irradiationtreatment of the radiation target so as to provide a neuralfunction-altering dose of radiation at the target and a safe luminaldose of radiation at the blood/vessel boundary.
 2. The method of claim1, wherein the nerve comprises a renal plexus, and wherein theirradiation treatment is planned so as to provide a decreasing dosegradient between the target and the blood/vessel boundary.
 3. The methodof claim 2, wherein the blood vessel comprises an aorta or a renalartery.
 4. (canceled)
 5. The method of claim 2, wherein the target isoffset from the blood/vessel boundary by an offset distance within arange from about 0.25 mm to about 6 mm and wherein the offset distancevaries longitudinally along the boundary within a range from about 0.5mm to about 3 mm.
 6. (canceled)
 7. The method of claim 1, furthercomprising adjusting a pattern of beams of the radiation to compensatefor movement of the blood vessel wall, the movement due to at least oneof a respiration, or a bodily shift of the patient, and wherein thepattern of beams are not adjusted in response to a heartbeat of thepatient body.
 8. The method of claim 1, further comprising outputtingthe planned irradiation treatment onto a plurality of slices of twodimensional image data.
 9. The method of claim 1, wherein the input isreceived on a display, the display facilitating the input by snappingthe input of the radiation target relative to a location on the threedimensional model.
 10. The method of claim 9, wherein the threedimensional model comprises a surface radially offset from theidentified blood/vessel boundary surface and the display facilitates theinput by snapping the input of the radiation target onto the surface ofthe three dimensional model.
 11. The method of claim 1, wherein theirradiation treatment comprises a plurality of intersecting beams andthe method further comprises expanding the irradiation treatment ofintersecting radiation beams along a longitudinal axis of theblood/vessel boundary surface such that renal nerve activity is reducedso as to treat hypertension.
 12. The method of claim 1, furthercomprising generating an ionizing radiation treatment plan based uponthe treatment pattern and projecting a dose cloud to the threedimensional model based upon the treatment plan so as to verify the doseof radiation along the blood/vessel boundary is sufficiently low toinhibit hyperplasia.
 13. The method of claim 1, wherein the lesionpattern comprises one or more annular circumferential segments.
 14. Themethod of claim 1, wherein the nerves comprise at least one of a celiacganglion, a superior mesenteric ganglion, an aorticorenal ganglion,nerves in the renal ostium region, and nerves in the renal arterybranching region.
 15. A radiosurgical system for denervation of apatient body, the system comprising: an image capture device foracquiring image data from a blood vessel adjacent to a nerve; a display;and a processor system coupling the image capture device to the display,the processor comprising: a modeling module configured for identifying athree dimensional boundary surface between blood and the blood vesselfrom the image data and for transmitting three dimensional model data tothe display in response thereto; an input module for receiving userinput data relative to the three dimensional model so as to identify aradiation target offset from the blood/vessel boundary surface; and aplanning module configured for planning a pattern of ionizing radiationtreatment beams in response to the radiation target so as to reducenerve activity within the nerve and to limit radiation along theblood/vessel boundary.
 16. The system of claim 15, wherein the nervecomprises a renal plexus, and wherein the planning module is configuredto plan the irradiation treatment so as to provide a decreasing dosebetween the target and the blood/vessel boundary.
 17. The system ofclaim 16, wherein the blood vessel comprises an aorta or a renal artery.18. (canceled)
 19. The system of claim 16, wherein the target is offsetfrom the blood/vessel boundary by an offset distance within a range fromabout 0.25 mm to about 6 mm.
 20. The system of claim 19, wherein theoffset distance varies longitudinally along the boundary within a rangefrom about 0.5 mm and 3.0 mm.
 21. The system of claim 15, wherein theplanning module is configured to output the ionizing radiation treatmentpattern for denervation of the adjacent nerve onto a plurality slices oftwo dimensional image data.
 22. The system of claim 15, wherein the userinput data is received on the display, the display facilitating theinput by snapping the input of the radiation target relative to alocation on the three dimensional model.
 23. The system of claim 22,wherein the three dimensional model data comprises a surface radiallyoffset from the identified blood/vessel boundary surface and the displayfacilitates the input by snapping the input of the radiation target ontothe surface of the three dimensional model.
 24. The system of claim 15,wherein the planning module is further configured to expand a treatmentpattern of intersecting radiation beams along a longitudinal axis of theblood/vessel boundary surface such that renal nerve activity is reducedso as to treat hypertension.
 25. The system of claim 15, wherein theplanning module is configured to generate an ionizing radiationtreatment plan based upon the user input and is further configured toproject a dose cloud to the three dimensional model based upon thetreatment pattern so as to verify the dose of radiation along theblood/vessel boundary is sufficiently low to inhibit hyperplasia. 26.The system of claim 15, wherein the target comprises one or more annularcircumferential segments and wherein the nerves comprise at least one ofa celiac ganglion, a superior mesenteric ganglion, an aorticorenalganglion, nerves in the renal ostium region, and nerves in the renalartery branching region.
 27. (canceled)
 28. A non-transitory computerreadable medium with computer executable instruction stored thereon fordeveloping a radiosurgical renal denervation treatment plan, the methodcomprising: acquiring image data from a blood vessel adjacent to anerve; generating a three dimensional model by identifying a boundarysurface between the blood vessel and blood flowing therein from theimage data; receiving input regarding a radiation target with referenceto an image of the three dimensional model, wherein the target is offsetfrom the blood/vessel boundary surface; and planning an irradiationtreatment of the radiation target so as to provide a neuralfunction-altering dose of radiation at the target and a safe luminaldose of radiation at the blood/vessel boundary; generating an ionizingradiation treatment plan based upon the user input; projecting a dosecloud to the three dimensional model based on the treatment plan; andoutputting information regarding the planned lesion pattern and the dosecloud onto the two dimensional image data slices.
 29. The method ofclaim 28, wherein the nerves comprise at least one of a renal plexus, aceliac ganglion, a superior mesenteric ganglion, an aorticorenalganglion, nerves in the renal ostium region, and nerves in the renalartery branching region.
 30. The method of claim 29, wherein the surfaceis a layer between an epithelial cell layer and an outer edge of theblood vessel adventitia.
 31. The method of claim 28, further comprisingevaluating the dose cloud to ensure the safe luminal dose of radiationat the blood/vessel boundary.